Autocomplete REPL commands

Author: vladimyr

src/module/repl.wren

@@ -287,6 +287,16 @@ class Repl {
     // Only complete if the cursor is at the end.
     if (_cursor != _line.count) return null
 
+    if (Command.isCommand(_line)) {
+      for (entry in COMMANDS) {
+        var command = entry[0]
+        var line = _line.trimStart()
+        if (command.startsWith(line)) {
+          return command[line.count..-1]
+        }
+      }
+    }
+
     for (name in Meta.getModuleVariables("repl")) {
       // TODO: Also allow completion if the line ends with an identifier but
       // has other stuff before it.

src/module/repl.wren.inc

@@ -289,6 +289,16 @@ static const char* replModuleSource =
 "    // Only complete if the cursor is at the end.\n"
 "    if (_cursor != _line.count) return null\n"
 "\n"
+"    if (Command.isCommand(_line)) {\n"
+"      for (entry in COMMANDS) {\n"
+"        var command = entry[0]\n"
+"        var line = _line.trimStart()\n"
+"        if (command.startsWith(line)) {\n"
+"          return command[line.count..-1]\n"
+"        }\n"
+"      }\n"
+"    }\n"
+"\n"
 "    for (name in Meta.getModuleVariables(\"repl\")) {\n"
 "      // TODO: Also allow completion if the line ends with an identifier but\n"
 "      // has other stuff before it.\n"